It is never safe to develop Java applets. It was a silly concept when it was devised, and it's still a silly concept today. We aren't developing ActiveX control

It is never safe to develop Java applets. It was a silly concept when it was devised, and it's still a silly concept today. We aren't developing ActiveX controls either, right? If you have an environment where you need a full client, and the developer is trusted, use Webstart: You have to actively accept something on Webstart. If you do not trust the developer, make the interface in a regular webpage.